LOL Man I love these posts! All true, true, true. I've experienced all if this and some.
I hate it when:
1) Our church goes to another church for a second service and after the home church finishes, their musicians stand behind our musicians when we go up and hawk us like we came to put on a show for them or something.
2) When the musican for a soloist is late, so you start to play for soloist and he/she gets there in the middle of the song. Then they sneak up on you to bump you off the organ, but there is a tight space up there so you have to sit on the edge of the bench while they play. Very unconfortable!
3) I play a congregational hymn in a jazzy style and there is a bass player playing it quartet style.
a) A bass player comes in and sets up all his gear and decides to play with you and he don't know none of the songs.
b) A bass player comes in with a phat 6 string bass and won't play the bassline. He's busy soloing all over the place, leaving it up to me to play my own bass.

Then when I start to play the basslines, he stops soloing to play the bass, clashing with me.

4) You are visiting another church and they have one of those old house organs that don't have drawbars and lights up like one of those old Casio keyboards. And sounds like one too! And your choir members take one look at it and shake their head and pat you on the back. LOL
5) When you really need to leave (like for a dinner date, or trying to catch the shed on the other side of town) and the visiting church does not bring a musician and you have to play for them. Then you put your finger up so you can tip out of the church after they are done, but someone catches you on the way out and asks if you would play for them. After that, you then you put your finger up to tip out again and the director for another guest church stops you in the isle to play for their church.
argg!!